Electromagnet.



, PATENTED JULY 14 D. L. LINDQUIST- ELBCTROMAGNET.

APPLICATION FILED IAB. 26, 1903.

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INVENTOR ELEGTRO'MAGNBT.

APPLICATION FILED MAR. 25, 1903.

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No. 733,549. PATENTED JULY 14. 1903-. D. L. LINDQUIST.

ELECTROMAGNET.

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UNITED STATES Fatented uly I4,

APATENT OEEICE.l

ELECTROMAGNET.

SPECIFICATION forming part of Letters Patent No. 733,549, dated July 14,1903. Application filed March 25, 1903. Serial No. 149,500. (No model.)

To @ZZ whom it may 00711007172.:

Be it known that I, DAVID L. LINDQUIST, of Yonkers, Westchester county,New York, have invented a new and useful Improvement in Electromagnets,of which the following is a specification.

The invention relates to an electromagnet intended for operation with analternating current. l

The object is to prevent the noisy vibration of the magnet-armature dueto the change from maximum to Zero of the current in the coils.

The invention consists, broadly, in an electromagnet-core, a pluralityof coils wound on said core extending transversely a polar face thereofand symmetrically disposed with reference to an axis perpendicular toand passing through the center of said polar face, and an armature infront of and movable toward said face. Vhen said magnet is energized byan alternating current, it exerts a substantially constant pull upon itsarmature, holding the same quiet and without chattering.

In the accompanying drawings, Figure lis a section of my electromagnetand armature on the line @c a: of Fig. 2. Fig. 2 is a section on theline 'y y of Fig. l. Fig. 3 is a top view. Figs. 4 to 1l, inclusive, arediagrams illustrating various modifications in the arrangement ofmagnet-coils and connections. Figs. 4 and 5 show the magnet adapted to athreephase current with the coils in star connection, andFigs. 6 and 7the same with the coils in delta connection. Figs. 8 and 9 show themagnet-field wound for two-phase current, and Figs. 10 and 1l for asingle-phase current.

Similar letters of reference indicate like parts.

The core A is preferably laminated and of symmetrical closed figure. Itis here shown in the form of a hollow cylinder or ring; but this shapeis not essential. Upon the core are wound the coils B C D. The coils aresymmetrically disposed upon the core with reference to the axisthere0f,which is of course perpendicular to the polar faces E F. Thecoils extend transversely said polar faces.

The armature Gis preferably of closed and symmetrical figure and may beprovided on the face which is in juxtaposition to the polar face of themagnet with recesses to receive the magnet-coils when said armature isattracted to said polar face. The advantage of this recessedconstruction is that it tends to prevent magnetic leakage.

The coils may extend entirely across the polar faces diametrically, asshown in Fig. 3, or partially across, as when they are wound around thebody of a ring-core, as illustrated in Fig. 4. In the latter case theyare symmetrically disposed around said ring.

The armature G is preferably placed in a metal cup K, which is receivedwithin the cylindrical casing L, held by the brackets M on any suitableback plate or other support. Within the casing L are lugs N, havingadjustingscrews O, upon which the armature rests when not attracted tothe magnet and by means of which the extent of' its path of movement toand from the magnet-face can be regulated. On the upper side of easing Lare bracket-arms P, in which the magnet is detachably secured bytheset-screws Q.

Referring now to the winding diagrams and the connections there shown,in Figs. 4 to 9 the main three-phase conductors are represented at a b cand connect to the usual converter d, which in turn connects with thethree contact-levers cfg, which are actuated by the handle h to make andbreak circuit with the terminals j k Z. Said terminals respectivelyconnect with the coil-sections. In Fig. 4 the coils are each wound intwo sections B B O C D D directly upon the ringbody, and these sectionsare connected in star, as shown. In Fig. 5 the coils are disposeddiametrically the polar faces, as in Fig. 3, and are similarlyconnected. In Fig. 6 the winding is the same as in Fig. 4, and in Fig. 7it is the same as in Fig. 5, the difference being in the connection ofthe coils or pairs of coil-sections in delta instead of in star. In Figs8 to 1l, inclusive, there are but two coils B C or pairs of coils B B CC', whereby Figs. S and 9 become adapted for two-phase current. In Figs.l0 and ll but two main conductors and two contact-levers and terminalsare used to suitasingle-phase current, which, however, goes to the splitcircuit of the magnet. One branch of this cir cuit contains an ohmicresistance, so as to get a phase difference, which should be as nearninety degrees as possible to obtain the constant pull. Of courseinstead of a resistance a single-phase motor may be introduced into onebranch of the magnet-circuit, lthe direct current on the magnet thenlagging about ninety degrees behind the voltage, While the current inthe branch through the motor is almost in phase With the voltage. In allcases there Will be produced in the magnet-core a rotary lield whichwill be endless in the direction of rotation in both armature and core.Because of the symmetrical Winding of the coils on the magnet-core theresultant action upon the armature Will be a uniform and constant pull,which will bring the armature to its final attracted position and holdit there Without producingin said armature the usual noisy vibrationsdue to changes in the magnetic flux, which have hitherto been regardedas unavoidable in electromagnets energized by an alternating current.

I claiml. An electromagnet-core, a plurality of coils Wound on said coreextending transversely a polar face thereof and symmetrically disposedWith reference to an axis perpendicular to and passing through thecenter of said polar face and an armature in front of and movable towardand from said face.

2. An electromagnet-core, a plurality of coils Wound on said core andextending transversely a polar face thereof and symmetrically disposedwith reference to and intersected by an axis perpendicular to andpassing through the center of said polar face and an armature in frontof and movable toward and from said face.

3. An electromagnet-core, a plurality of coils wound on said core andsymmetrically disposed With reference to an axis perpendicular to andpassing through the center of a polar face, a movable armature in frontof said face and means for guiding said armature in its path of movementtoward and from said face.

4. An electromagnetcore, a plurality of 'reame coils Wound on said coreand symmetrically disposed with reference to an axis perpendicular toand passing through the center of a polar face, a movable armature infront of said face and means for guiding said armature in its path ofmovement toward and from said face and means for adjusting the extent ofsaid path.

5. A cylindrical electromagnet-core, a plurality of coils symmetricallydisposed thereon each coil being intersected by the axis of saidcylinder and an armature facing one end of said core and movable to andfrom said end.

6. A cylindrical electromagnet-core, a plurality of coils symmetricallydisposed With reference to the axis of said cylinder each coil beingintersected by said axis and a cylindrical armature in front of a polarface of said core; the said armature being movable to and from said faceand provided With recesses to receive the coils projecting therefrom.v

7. A cylindrical electromagnet-core, a plurality of coils thereon, .eachcoil being intersected by the axis of said cylinder and the anglessubtended by adjacent coils being equal, and a cylindrical armaturedisposed in front of and movable to and from a polar face of said core.

S. The combination of the cylindrical casing L, the cylindricalelectromagnet-core A having symmetrically-disposed coils B C D,supported above said casing and the cylindrical armature Gr Within saidcasing.

9. The combination of the cylindrical casing L, the cylindricalelectromagnet-core A having symmetrically-disposed coils B C D, meansfor detachably supporting said core above and on said casing, thecylindrical armature G Within said casing and adjustable supports O forsaid armature.

In testimony whereof I have signed my name to this specification in thepresence of tWo subscribing Witnesses.

DAVID L. LINDQUIST.

Witnesses:

I. A. VAN WART, WM. H. SIEGMAN.

